The research outlined in this proposal is aimed at understanding the fundamental chemistry taking place at the copper-centers of Dopamine Beta Hydroxylase and Peptideglycine alpha Hydroxylating Monooxygenase. Both enzymes contain two structurally isolated and spectroscopically distinct copper centers and catalyze the hydroxylation of hydrocarbon substrates using dioxygen as the sole oxidant. Synthetic models will be made to mimic both of these centers. One series of models that will be prepared is a mononuctear copper center aimed at mimicking the reactive properties of the metal-center that is proposed to be the site where hydrocarbon hydroxylation takes place through a supposed CuII-hydroperoxo intermediate. Studies will be performed to elucidate the mechanism of substrate oxidation by this copper-center mimic. Dinuclear models will be made containing mimics for both copper-cites, Studies with the dinuclear complexes will be aimed at understanding how the two centers work in concert to generate the CuII-hydroperoxo species.